Indexing mechanism for grinding and other machines



2 Sheets-Sheet 1 J. w. SNARY INDEXING MECHANISM FOR GRINDIANG AND OTHER MACHINES Filed Jan. 2. 1926 April 26 1927.

April 26,1927.

J.'w. sNARR.Y

INDEXING MECHANISM FOR 661mm AND OTHER MAcHINEs Filed Jan. 2 1926 2 sheets-sheet 2 1 ifi"- s.

taser fics.

JOHN WILDsMrTH sNAERY,. or BrnMrNGHAM, ENGLAND, AssI'GNon vro THE GEA GRINDr-NG COMPANY LIMITED, or BIRMINGHAM, ENGLAND.

INDEXINGMnorIANrslvr Eon'GnrNnrNG-AND OTHER. MACHINES.

Application med January 2, ieee,` serial No. 79,046, and ineat Britain May' 25, 1925.

This invention has for 'its object to provide improved indexing lor dividingv mechanism for usel in grinding the teeth of gear wheels and the like, and tor other similar purposes in which a high degree of accuracy is required. d

The invention comprises the combination of lan indexing or dividing plate mounted on a spindle. and formed with a toothed periphery, one face in each tooth being disposed radially to the centrey of the plate, a positioning pawl pivoted on a stationary pivot and formed with a flat endadapted kto coact with the radial face of each ofthe teeth, a stop whichV limits the extent to which the saidV pawl can nieve into engagement with any tooth, an oscillatory arm carrying an actuating pawl which serves to move the plate from one position to the next, means forv reciprocating thearm, said means including a spring whichr enables the actuating pawl to press the plate with definite pressure against the positioning pawl, and a cam for intermittently disconnecting the positioning pawl from the plate.

In the accompanying sheet of explanatory drawings:-

Figure l is a sectional side elevation and Figure 2 a. plan showing a divided or in.

dexing mechanism constructed in accordance with this invention,

In applying the invention as shown to machine-s for grinding the teeth of gear wheels and other like purposes, an indexing plate a is secured to a spindle b connected to the worl piece.. This plate has formed on its periphery a number of equally spaced teeth c, the distance between which corresponds to the angular movementto be imparted to the work piece between successive grinding operations. In the construction shown in the drawings the teeth care formed in the periphery of the plate a by cutting a pair oi' notches at each of the proper positions on the plate, the tooth being formed by the portion between the notches. One face (d) of each tooth is made to coincide accurately with a radius through the centre of the plate. The opposite face may be slightly inclined.

Adjacent tothe plate is pivoted on a fixed pivot a positioning pawl e the free end ofv which is flat and is adapted to co-act with and serve as an abutment for the radial face l.

of each of the teeth. To ensure that the flat end ofthe positioning pawl shall always occupy a truly radial position when in action a vprojecting shoulder f on the "free" end ofl the vpawl is arranged to rest on' anadjustable stop g. The stop is so adjusted thatwhen the shoulder .of the pawl rests on it therend tace of the vpawl coincides accurately; with a radius through the centre ot' the indexing` plate. The pawl is pressed on the stopby aweight orplunger h acting on the pawl; itv desired this spring.

plunger may be loaded by a v l F or lifting the'pawlout of engagement with theindexing plate an oscillatory cam z' isV employed, the cam being arranged in com-k bination with an oscillatory arm j which car# ries the plate actuating pawl Ic. This pawl is pivoted on the arm in such a manner that in one direction of motion it passes idly over the periphery of the indexing plate, whilst in the other direction of motion itengagesl a tooth (under the action of a spring m.) and moves ,the plate through the required angular distance. During the idle movement, the

cam by acting on a peg or roller Z lifts the positioning pawl out of action. The pawl is allowed by the cam tore-engage the plate towards the end of the nextmovement of the plate. dotted lines at t) may be employed to prevent movement oi" the plate during the idle motion of the actuating pawl.

Oscillation oli' the arm is preferably etected by a reciprocating slide n adapted to engage the arm through a fork 0 and roller p or other suitable device. The slide is actuated rom a crank g, and on the connecting piece r between the lslide and cranlra compression spring .s' is arranged. The motion is imparted from the vcrank tothe slide through the spring. At thev end ot each operative movement, the. spring is compressed to a predetermined amount, and the spring causes the actuating pawl to press the indexing plate firmly against the positioning pawl.

By this invention I am able to attain a high degree of accuracy in a very simple manner. Y

Having thus described my invention what A locking `pawl (as indicated by- I claimv as new and desire to secure by Letwith a toothed periphery, one face` in each tooth beingdi'sposed radially to the centre of the plate, a spindle on which the plate' is mount-ed, a: positioning pawl. formed with# a flat end adapted. to/coac't. Withtheradial face of each of the teeth, a stationary pivot lfor the positi'oningpawvl, astop which limits the extent to which thev positioning pavvl can move into engagement With any tooth, an 4oscillatory arm. carrying an actuating pawl adapted,k to move theiplate from one po.- sition to the next, means for; reciprocating the arm, said means includinga springwhich v enables the actuating pawl to press the plate tooth ybeing disposed radially tol the centre of the plate, a. spindle on Which the plate is mounteda positioning paWl, a stationary pivotfor said pawl, the pavvl-be-ing provided with a lat end adapted to -coact with the radial face of each of the teeth on the plate, a. stop ada-ptednt'o:y limit the extent to which the said 'p'aWl-v can move"y into engagement with any tooth, an oscillatory arm, an actuating p'avvlcarriedon said? arm and adapt-k ed to lmove the` plate from one position to theA next, a reciprocatory"member' for oscillating the arm, a crank for actuating thereciprocatory member, a springin conjunction with the crank and' reciprocatory member whereby the actuating pawl can press' the plate, WithA definite pressure' against' the positioning paWl, and: a cam adapted to intermittently disconnect the positioning pawl from the plate, substantially as described'.

y3. In` indexing-` or dividing mechanism as claimed in claim l', the'. combination with the positioning pawl', y ofrk means for lpressing it into contact' With they stop, substantially as, describ'edl y A L y In, testimony whereofj have signedy my name to this. speciiication;

JOHN` WILDSMITH sNARRY'. 

